html {
    background: #eee;
}
body {
    font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
    background: #fff;
    margin: 0 auto;
    max-width: 640px;
    padding: 40px;
}
header > h1 {
    font-size: 32px;
}
main > h1 {
    font-size: 24px;
}
footer {
    margin-top: 1rem;
    border-top: 1px solid #ccc;
    padding-top: 1rem;
    font-size: 12px;
}

